Long-distance high-voltage DC is a thing, but I’m pretty sure that the vast majority is still AC.
Yeah, there’s not much of it in the US (at least as of 2018), just a couple out west, some in the Dakotas/Minnesota, Quebec/New England, and some undersea Mid-Atlantic. I think it’s more common in Europe, though mainly as interconnects between national grids. HVDC is great for that because you don’t need to maintain phase sync between grids (hello Texas, are you listening?), but otherwise it’s not all that common yet.